How to make a net of nodes in blender?
I think the link @Computer Guy provided solves the problem, but as the link-only answers may become invalid I post a step by step solution how to do it (which uses the Wireframe Modifier, dupliverts/particle system and Camera DOF).


Create a mesh you want (in my case I use a poor Suzanne again :)) and triangulate it with Ctrl+T. You don't need to do it though if you want to have a quad based wire.


With the object selected go to the Modifiers header and give it a Wireframe Modifier. Set its thickness as you like.


Select your mesh and give it an Emission shader in a Node Editor (material). Set its Strenght value as you like. Also set the World color to pure black.


Now select your mesh, press Shift+S-->Cursor to Selected. Add a Sphere there (make sure it shares the same origin point as your mesh). Scale it as you want then press Ctrl+A-->Rot&amp;Scale to apply transformations to it.


Now select newly added Sphere, then your mesh and press Ctrl+P-->Set Parent To-->Object. Select your mesh in Object Mode and go to the Object header-->Duplication panel and press the Verts button.
NOTE: You may achieve the similar result using the Particle System, but I won't cover it now (maybe I'll edit my answer to explain it later).


Set a material of a Sphere as pictured below (mix an Emission and Transparent shaders). Play with the Factor of a Mix Shader to fit the reference.


With your mesh selected in the Object Mode press Shift+Ctrl+A to make the duplicated Spheres a real/editable objects.



Finally select your Camera, go to the Camera Data header-->Depth of Field panel. Use a dropper icon to select one of the spheres that is closest to the camera and increase the camera's Radius size a bit. It'll blur the background as in the reference you provided.